Soybean cultivar 61646251

ABSTRACT

A novel soybean cultivar, designated 61646251, is disclosed. The invention relates to the seeds of soybean cultivar 61646251, to the plants of soybean 61646251 and to methods for producing a soybean plant produced by crossing the cultivar 61646251 with itself or another soybean variety. The invention further relates to hybrid soybean seeds and plants produced by crossing the cultivar 61646251 with another soybean cultivar.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinctive soybean cultivar,designated 61646251. There are numerous steps in the development of anynovel, desirable plant germplasm. Plant breeding begins with theanalysis and definition of problems and weaknesses of the currentgermplasm, the establishment of program goals, and the definition ofspecific breeding objectives. The next step is selection of germ plasmthat possess the traits to meet the program goals. The goal is tocombine in a single variety an improved combination of desirable traitsfrom the parental germplasm. These important traits may include higherseed yield, resistance to diseases and insects, better stems and roots,tolerance to drought and heat, and better agronomic quality.

Choice of breeding or selection methods depends on the mode of plantreproduction, the heritability of the trait(s) being improved, and thetype of cultivar used commercially (e.g., F₁ hybrid cultivar, purelinecultivar, etc.). For highly heritable traits, a choice of superiorindividual plants evaluated at a single location will be effective,whereas for traits with low heritability, selection should be based onmean values obtained from replicated evaluations of families of relatedplants. Popular selection methods commonly include pedigree selection,modified pedigree selection, mass selection, and recurrent selection.

The complexity of inheritance influences choice of the breeding method.Backcross breeding is used to transfer one or a few favorable genes fora highly heritable trait into a desirable cultivar. This approach hasbeen used extensively for breeding disease-resistant cultivars. Variousrecurrent selection techniques are used to improve quantitativelyinherited traits controlled by numerous genes. The use of recurrentselection in self-pollinating crops depends on the ease of pollination,the frequency of successful hybrids from each pollination, and thenumber of hybrid offspring from each successful cross.

Each breeding program should include a periodic, objective evaluation ofthe efficiency of the breeding procedure. Evaluation criteria varydepending on the goal and objectives, but should include gain fromselection per year based on comparisons to an appropriate standard,overall value of the advanced breeding lines, and number of successfulcultivars produced per unit of input (e.g., per year, per dollarexpended, etc.).

Promising advanced breeding lines are thoroughly tested and compared toappropriate standards in environments representative of the commercialtarget area(s) for three or more years. The best lines are candidatesfor new commercial cultivars; those still deficient in a few traits maybe used as parents to produce new populations for further selection.

These processes, which lead to the final step of marketing anddistribution, usually take from eight to 12 years from the time thefirst cross is made. Therefore, development of new cultivars is atime-consuming process that requires precise forward planning, efficientuse of resources, and a minimum of changes in direction.

A most difficult task is the identification of individuals that aregenetically superior, because for most traits the true genotypic valueis masked by other confounding plant traits or environmental factors.One method of identifying a superior plant is to observe its performancerelative to other experimental plants and to a widely grown standardcultivar. If a single observation is inconclusive, replicatedobservations provide a better estimate of its genetic worth.

The goal of plant breeding is to develop new, unique and superiorsoybean cultivars and hybrids. The breeder initially selects and crossestwo or more parental lines, followed by repeated selfing and selection,producing many new genetic combinations. The breeder can theoreticallygenerate billions of different genetic combinations via crossing,selfing and mutations. The breeder has no direct control at the cellularlevel. Therefore, two breeders will never develop the same line, or evenvery similar lines, having the same soybean traits.

Each year, the plant breeder selects the germplasm to advance to thenext generation. This germplasm is grown under unique and differentgeographical, climatic and soil conditions, and further selections arethen made, during and at the end of the growing season. The cultivarswhich are developed are unpredictable. This unpredictability is becausethe breeder's selection occurs in unique environments, with no controlat the DNA level (using conventional breeding procedures), and withmillions of different possible genetic combinations being generated. Abreeder of ordinary skill in the art cannot predict the final resultinglines he develops, except possibly in a very gross and general fashion.The same breeder cannot produce the same cultivar twice by using theexact same original parents and the same selection techniques. Thisunpredictability results in the expenditure of large amounts of researchmonies to develop superior new soybean cultivars.

The development of new soybean cultivars requires the development andselection of soybean varieties, the crossing of these varieties andselection of superior hybrid crosses. The hybrid seed is produced bymanual crosses between selected male-fertile parents or by using malesterility systems. These hybrids are selected for certain single genetraits such as pod color, flower color, pubescence color or herbicideresistance which indicate that the seed is truly a hybrid. Additionaldata on parental lines, as well as the phenotype of the hybrid,influence the breeder's decision whether to continue with the specifichybrid cross.

Pedigree breeding and recurrent selection breeding methods are used todevelop cultivars from breeding populations. Breeding programs combinedesirable traits from two or more cultivars or various broad-basedsources into breeding pools from which cultivars are developed byselfing and selection of desired phenotypes. The new cultivars areevaluated to determine which have commercial potential.

Pedigree breeding is used commonly for the improvement ofself-pollinating crops. Two parents which possess favorable,complementary traits are crossed to produce an F₁ An F₂ population isproduced by selfing one or several F₁'s. Selection of the bestindividuals may begin in the F₂ population; then, beginning in the F₃,the best individuals in the best families are selected. Replicatedtesting of families can begin in the F₄ generation to improve theeffectiveness of selection for traits with low heritability. At anadvanced stage of inbreeding (i.e., F₆ and F₇), the best lines ormixtures of phenotypically similar lines are tested for potentialrelease as new cultivars.

Mass and recurrent selections can be used to improve populations ofeither self- or cross-pollinating crops. A genetically variablepopulation of heterozygous individuals is either identified or createdby intercrossing several different parents. The best plants are selectedbased on individual superiority, outstanding progeny, or excellentcombining ability. The selected plants are intercrossed to produce a newpopulation in which further cycles of selection are continued.

Backcross breeding has been used to transfer genes for a simplyinherited, highly heritable trait into a desirable homozygous cultivaror inbred line which is the recurrent parent. The source of the trait tobe transferred is called the donor parent. The resulting plant isexpected to have the attributes of the recurrent parent (e.g., cultivar)and the desirable trait transferred from the donor parent. After theinitial cross, individuals possessing the phenotype of the donor parentare selected and repeatedly crossed (backcrossed) to the recurrentparent. The resulting plant is expected to have the attributes of therecurrent parent (e.g., cultivar) and the desirable trait transferredfrom the donor parent.

The single-seed descent procedure in the strict sense refers to plantinga segregating population, harvesting a sample of one seed per plant, andusing the one-seed sample to plant the next generation. When thepopulation has been advanced from the F₂ to the desired level ofinbreeding, the plants from which lines are derived will each trace todifferent F₂ individuals. The number of plants in a population declineseach generation due to failure of some seeds to germinate or some plantsto produce at least one seed. As a result, not all of the F₂ plantsoriginally sampled in the population will be represented by a progenywhen generation advance is completed.

In a multiple-seed procedure, soybean breeders commonly harvest one ormore pods from each plant in a population and thresh them together toform a bulk. Part of the bulk is used to plant the next generation andpart is put in reserve. The procedure has been referred to as modifiedsingle-seed descent or the pod-bulk technique.

The multiple-seed procedure has been used to save labor at harvest. Itis considerably faster to thresh pods with a machine than to remove oneseed from each by hand for the single-seed procedure. The multiple-seedprocedure also makes it possible to plant the same number of seeds of apopulation each generation of inbreeding. Enough seeds are harvested tomake up for those plants that did not germinate or produce seed.

Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in one of several referencebooks (e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr,1987).

Proper testing should detect any major faults and establish the level ofsuperiority or improvement over current cultivars. In addition toshowing superior performance, there must be a demand for a new cultivarthat is compatible with industry standards or which creates a newmarket. The introduction of a new cultivar will incur additional coststo the seed producer, the grower, processor and consumer; for specialadvertising and marketing, altered seed and commercial productionpractices, and new product utilization. The testing preceding release ofa new cultivar should take into consideration research and developmentcosts as well as technical superiority of the final cultivar. Forseed-propagated cultivars, it must be feasible to produce seed easilyand economically.

Soybean, Glycine max (L), is an important and valuable field crop. Thus,a continuing goal of plant breeders is to develop stable, high yieldingsoybean cultivars that are agronomically sound. The reasons for thisgoal are obviously to maximize the amount of grain produced on the landused and to supply food for both animals and humans. To accomplish thisgoal, the soybean breeder must select and develop soybean plants thathave the traits that result in superior cultivars.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel soybean cultivar,designated 61646251. This invention thus relates to the seeds of soybeancultivar 61646251, to the plants of soybean 61646251 and to methods forproducing a soybean plant produced by crossing the soybean 61646251 withitself or another soybean line.

Thus, any such methods using the soybean variety 61646251 are part ofthis invention: selfing, backcrosses, hybrid production, crosses topopulations, and the like. All plants produced using soybean variety61646251 as a parent are within the scope of this invention.Advantageously, the soybean variety could be used in crosses with other,different, soybean plants to produce first generation (F₁) soybeanhybrid seeds and plants with superior characteristics.

In another aspect, the present invention provides for single geneconverted plants of 61646251. The single transferred gene may be adominant or recessive allele. Preferably, the single transferred genewill confer such traits as herbicide resistance, insect resistance,resistance for bacterial, fungal, or viral disease, male fertility, malesterility, enhanced nutritional quality, and industrial usage. Thesingle gene may be a naturally occurring soybean gene or a transgeneintroduced through genetic engineering techniques.

In another aspect, the present invention provides regenerable cells foruse in tissue culture of soybean plant 61646251. The tissue culture willpreferably be capable of regenerating plants having the physiologicaland morphological characteristics of the foregoing soybean plant, and ofregenerating plants having substantially the same genotype as theforegoing soybean plant. Preferably, the regenerable cells in suchtissue cultures will be embryos, protoplasts, meristematic cells,callus, pollen, leaves, anthers, roots, root tips, flowers, seeds, podsor stems. Still further, the present invention provides soybean plantsregenerated from the tissue cultures of the invention.

Definitions

In the description and tables which follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

Maturity Date. Plants are considered mature when 95% of the pods havereached their mature color. The number of days are either calculatedfrom August 31 or from the planting date.

Seed Yield (Bushels/Acre). The yield in bushels/acre is the actual yieldof the grain at harvest.

Lodging Resistance. Lodging is rated on a scale of 1 to 9. A score of 9indicates erect plants. A score of 5 indicates plants are leaning at a450 angle in relation to the ground and a score of 1 indicates plantsare laying on the ground.

Phytophthora Tolerance. Tolerance to Phytophthora root rot is rated on ascale of 1 to 9, with a score of 9 being the best or highest toleranceranging down to a score of 1 which indicates the plants have notolerance to Phytophthora.

Emergence. This score indicates the ability of the seed to emerge whenplanted 3″ deep in sand and with a controlled temperature of 25° C. Thenumber of plants that emerge each day are counted. Based on this data,each genotype is given a 1 to 9 score based on its rate of emergence andpercent of emergence. A score of 9 indicates an excellent rate andpercent of emergence, an intermediate score of 5 indicates averageratings and a 1 score indicates a very poor rate and percent ofemergence.

Iron-Deficiency Chlorosis. Plants are scored 1 to 9 based on visualobservations. A score of 9 means no stunting of the plants or yellowingof the leaves and a score of 1 indicates the plants are dead or dyingcaused by iron-deficiency chlorosis, a score of 5 means plants haveintermediate health with some leaf yellowing.

Brown Stem Rot. This is a visual disease score from 1 to 9 comparing allgenotypes in a given test. The score is based on leaf symptoms ofyellowing and necrosis caused by brown stem rot. A score of 9 indicatesno symptoms. Visual scores range to a score of I which indicates severesymptoms of leaf yellowing and necrosis.

Shattering. The amount of pod dehiscence prior to harvest. Poddehiscence involves seeds falling from the pods to the soil. This is avisual score from 1 to 9 comparing all genotypes within a given test. Ascore of 9 means pods have not opened and no seeds have fallen out. Ascore of 5 indicates approximately 50% of the pods have opened, withseeds falling to the ground and a score of 1 indicates 100% of the podsare opened.

Plant Height. Plant height is taken from the top of soil to top node ofthe plant and is measured in centimeters.

Seed Protein Peroxidase Activity. Seed protein peroxidase activity isdefined as a chemical taxonomic technique to separate cultivars based onthe presence or absence of the peroxidase enzyme in the seed coat. Thereare two types of soybean cuftivars, those having high peroxidaseactivity (dark red color) and those having low peroxidase activity (nocolor).

Allele. Allele is any of one or more alternative forms of a gene, all ofwhich alleles relate to one trait or characteristic. In a diploid cellor organism, the two alleles of a given gene occupy corresponding locion a pair of homologous chromosomes.

Backcrossing. Backcrossing is a process in which a breeder repeatedlycrosses hybrid progeny back to one of the parents, for example, a firstgeneration hybrid F₁ with one of the parental genotypes of the F₁hybrid.

Essentially all the physiological and morphological characteristics. Aplant having essentially all the physiological and morphologicalcharacteristics means a plant having the physiological and morphologicalcharacteristics, except for the characteristics derived from theconverted gene.

Quantitative Trait Loci (QTL). Quantitative trait loci (QTL) refer togenetic loci that control to some degree numerically representabletraits that are usually continuously distributed.

Regeneration. Regeneration refers to the development of a plant fromtissue culture.

Single Gene Converted (Conversion). Single gene converted (conversion)plant refers to plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of a variety are recovered in additionto the single gene transferred into the variety via the backcrossingtechnique or via genetic engineering.

DETAILED DESCRIPTION OF THE INVENTION

Soybean cultivar 61646251 has superior characteristics and was developedfrom the cross 01718-90(2)×10305-1 RR. F₂ derived lines were tested inexperimental plots in 1996. From high-yielding lines, 30 F₄ derivedplant rows were evaluated during the winter of 1996-1997. In 1997, 25plant row selections were tested at six midwest locations. Based on 1996and 1997 data, 61646251 was advanced to Elite trials in 1998 and 1999.Table 1 shows 1998 and 1999 Elite Trial data from 14-16 locations.

Some of the criteria used to select in various generations include: seedyield, lodging resistance, emergence, disease tolerance, maturity, lateseason plant intactness, plant height and shattering resistance.

The cultivar has shown uniformity and stability, as described in thefollowing variety description information. It has been self-pollinated asufficient number of generations with careful attention to uniformity ofplant type. The line has been increased with continued observation foruniformity.

Soybean cultivar 61646251 has the following morphologic and othercharacteristics (based primarily on data collected at Adel, Iowa).

Variety Description Information

1. Seed Coat Color: (Mature Seed)—Yellow

2. Seed Coat Luster: (Mature Hand Shelled Seed)—Dull

3. Hilum Color: (Mature Seed)—Black

4. Cotyledon Color: (Mature seed)—Yellow

5. Leaflet shape: Ovate

6. Flower Color: White

7. Pod Color: Tan

8. Plant Pubescence Color: Light Tawny

9. Plant Habit: Indeterminate

10. Maturity Group: 11

11. Relative Maturity: 2.0

12. Plant Lodging Score: 7

13. Plant Height: 79 cm

14. Seed Content: % DM Protein: 41.2

% DM Oil: 21.2

15. Seed Size G/i 00 Seeds: 17.3

16. Physiological Responses:

Roundup Ready™ Herbicide: Resistant

Brown Stem Rot: Resistant

This invention is also directed to methods for producing a soybean plantby crossing a first parent soybean plant with a second parent soybeanplant, wherein the first or second soybean plant is the soybean plantfrom the line 61646251. Further, both first and second parent soybeanplants may be from the cultivar 61646251. Therefore, any methods usingthe cultivar 61646251 are part of this invention: selfing, backcrosses,hybrid breeding, and crosses to populations. Any plants produced usingcultivar 61646251 as a parent are within the scope of this invention.

As used herein, the term “plant” includes plant cells, plantprotoplasts, plant cells of tissue culture from which soybean plants canbe regenerated, plant calli, plant clumps, and plant cells that areintact in plants or parts of plants, such as pollen, flowers, embryos,ovules, seeds, pods, leaves, stems, roots, anthers and the like. Thus,another aspect of this invention is to provide for cells which upongrowth and differentiation produce a cultivar having essentially all ofthe physiological and morphological characteristics of 61646251.

Culture for expressing desired structural genes and cultured cells areknown in the art. Also as known in the art, soybeans are transformableand regenerable such that whole plants containing and expressing desiredgenes under regulatory control may be obtained. General descriptions ofplant expression vectors and reporter genes and transformation protocolscan be found in Gruber, et al., “Vectors for Plant Transformation, inMethods in Plant Molecular Biology & Biotechnology” in Glich, et al.,(Eds. pp. 89-119, CRC Press, 1993). Moreover GUS expression vectors andGUS gene cassettes are available from Clone Tech Laboratories, Inc.,Palo Alto, Calif. while luciferase expression vectors and luciferasegene cassettes are available from Pro Mega Corp. (Madison, Wis.).General methods of culturing plant tissues are provided for example byMaki, et al., “Procedures for Introducing Foreign DNA into Plants” inMethods in Plant Molecular Biology & Biotechnology, Glich, et al., (Eds.pp. 67-88 CRC Press, 1993); and by Phillips, et al., “Cell-TissueCulture and In-Vitro Manipulation” in Corn & Corn Improvement, 3rdEdition; Sprague, et al., (Eds. pp. 345-387) American Society ofAgronomy Inc., 1988. Methods of introducing expression vectors intoplant tissue include the direct infection or co-cultivation of plantcells with Agrobacterium tumefaciens, Horsch et al., Science, 227:1229(1985). Descriptions of Agrobacterium vectors systems and methods forAgrobacterium-mediated gene transfer provided by Gruber, et al., supra.

Useful methods include but are not limited to expression vectorsintroduced into plant tissues using a direct gene transfer method suchas microprojectile-mediated delivery, DNA injection, electroporation andthe like. More preferably expression vectors are introduced into planttissues using the microprojectile media delivery with the biolisticdevice Agrobacterium-medicated transformation. Transformant plantsobtained with the protoplasm of the invention are intended to be withinthe scope of this invention.

The present invention contemplates a soybean plant regenerated from atissue culture of a variety (e.g., 61646251) or hybrid plant of thepresent invention. As is well known in the art, tissue culture ofsoybean can be used for the in vitro regeneration of a soybean plant.Tissue culture of various tissues of soybeans and regeneration of plantstherefrom is well known and widely published. For example, reference maybe had to Komatsuda, T., et al., “Genotype X Sucrose Interactions forSomatic Embryogenesis in Soybean,” Crop Sci. 31:333-337 (1991);Stephens, P.A., et al., “Agronomic Evaluation of Tissue-Culture-DerivedSoybean Plants,” Theor. AppI. Genet. (1991) 82:633-635; Komatsuda, T.,et al., “Maturation and Germination of Somatic Embryos as Affected bySucrose and Plant Growth Regulators in Soybeans Glycine gracilis Skvortzand Glycine max (L.) Merr.,” Plant Cell, Tissue and Organ Culture,28:103-113 (1992); Dhir, S., et al., “Regeneration of Fertile Plantsfrom Protoplasts of Soybean (Glycine max L. Merr.): GenotypicDifferences in Culture Response, “Plant Cell Reports (1992) 11:285-289;Pandey, P. et al., “Plant Regeneration from Leaf and Hypocotyl Explantsof Glycine wightii (W. And A.) VERDC. var longicauda,” Japan J. Breed.42:1-5 (1992); and Shetty, K., et al., “Stimulation of In Vitro ShootOrganogenesis in Glycine max (Merrill.) by Allantoin and Amides,” PlantScience (1992) 81:245-251; as well as U.S. Pat. No. 5,024,944, issuedJun. 18, 1991 to Collins, et al., and U.S. Pat. No. 5,008,200, issuedApr. 16, 1991 to Rauch, et al., the disclosures of which are herebyincorporated herein in their entirety by reference. Thus, another aspectof this invention is to provide cells which upon growth anddifferentiation produce soybean plants having the physiological andmorphological characteristics of variety 61646251.

The cultivar 61646251 is similar to 01718-90. While similar to 01718-90,there are numerous differences including: 61646251 has the gene forresistance to the Roundup™ herbicides and 01718-90 does not contain thisgene. Additionally, 61646251 has black hila while 01718-90 has brownhila.

As shown in Table 1, soybean cultivar 61646251 yields higher thanCM2807, MP215E, 92B21, CX15ORR, AG1601, AG1901, AG-2001 and AP2002RR,with the increase over 5 comparisons being significant at the 0.01 levelof probability and the increase over 3 comparisons being significant atthe 0.05 level of probability.

Tables

In Table 1 that follows, the traits and characteristics of soybeancultivar 61646251 are compared to several competing varieties ofcommercial soybeans of similar maturity. In the tables, column 1 showsthe comparison number; column 2 is the year of the test; columns 3 and 4give the number of locations and number of observations, respectively.Column 5 indicates the genotype and column 6 shows the mean yield inbushels per acre. Column 7 presents the t value and columns 8 and 9present the critical t values at the 0.05% and 0.01% levels ofsignificants, respectively.

TABLE 1 PAIRED COMPARISONS Critical Critical Comp # Year # of Loc. # ofObs. Genotype Mean Yield t Value t @ .05 t @ .01 1 1998 14 40 6164625151.1 6.35** 1.68 2.43 CM2807 45.9 2 1998 14 40 61646251 51.1 3.53** 1.682.43 MP215E 46.6 3 1998 14 40 61646251 51.1 3.10** 1.68 2.43 92B21 47.24 1999 15 43 61646251 47.3 5.10** 1.68 2.42 CX150RR 42.0 5 1999 15 4361646251 47.3 4.34** 1.68 2.42 AG1601 43.6 6 1999 15 43 61646251 47.32.29* 1.68 2.42 AG1901 47.2 7 1999 15 43 61646251 47.3 2.10* 1.68 2.42AG2001 45.6 8 1999 16 46 61646251 46.0 1.77* 1.68 2.41 AP2002RR 44.3*Significant at .05 level of probability **Significant at .01 level ofprobability

When the term soybean plant is used in the context of the presentinvention, this also includes any single gene conversions of thatvariety. The term single gene converted plant as used herein refers tothose soybean plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of a variety are recovered in additionto the single gene transferred into the variety via the backcrossingtechnique. Backcrossing methods can be used with the present inventionto improve or introduce a characteristic into the variety. The termbackcrossing as used herein refers to the repeated crossing of a hybridprogeny back to the recurrent parent. The parental soybean plant whichcontributes the gene for the desired characteristic is termed thenonrecurrent or donor parent. This terminology refers to the fact thatthe nonrecurrent parent is used one time in the backcross protocol andtherefore does not recur. The parental soybean plant to which the geneor genes from the nonrecurrent parent are transferred is known as therecurrent parent as it is used for several rounds in the backcrossingprotocol (Poehlman & Sleper, 1994; Fehr, 1987). In a typical backcrossprotocol, the original variety of interest (recurrent parent) is crossedto a second variety (nonrecurrent parent) that carries the single geneof interest to be transferred. The resulting progeny from this cross arethen crossed again to the recurrent parent and the process is repeateduntil a soybean plant is obtained wherein essentially all of the desiredmorphological and physiological characteristics of the recurrent parentare recovered in the converted plant, in addition to the singletransferred gene from the nonrecurrent parent.

The selection of a suitable recurrent parent is an important step for asuccessful backcrossing procedure. The goal of a backcross protocol isto alter or substitute a single trait or characteristic in the originalvariety. To accomplish this, a single gene of the recurrent variety ismodified or substituted with the desired gene from the nonrecurrentparent, while retaining essentially all of the rest of the desiredgenetic, and therefore the desired physiological and morphological,constitution of the original variety. The choice of the particularnonrecurrent parent will depend on the purpose of the backcross, one ofthe major purposes is to add some commercially desirable, agronomicallyimportant trait to the plant. The exact backcrossing protocol willdepend on the characteristic or trait being altered to determine anappropriate testing protocol. Although backcrossing methods aresimplified when the characteristic being transferred is a dominantallele, a recessive allele may also be transferred. In this instance itmay be necessary to introduce a test of the progeny to determine if thedesired characteristic has been successfully transferred.

Many single gene traits have been identified that are not regularlyselected for in the development of a new variety but that can beimproved by backcrossing techniques. Single gene traits may or may notbe transgenic, examples of these traits include but are not limited to,male sterility, waxy starch, herbicide resistance, resistance forbacterial, fungal, or viral disease, insect resistance, male fertility,enhanced nutritional quality, industrial usage, yield stability andyield enhancement. These genes are generally inherited through thenucleus. Several of these single gene traits are described in U. S. Pat.Nos. 5,959,185, 5,973,234 and 5,977,445, the disclosures of which arespecifically incorporated herein by reference.

A further aspect of the invention relates to tissue culture of soybeanplants designated 61646251. As used herein, the term “tissue culture”indicates a composition comprising isolated cells of the same or adifferent type or a collection of such cells organized into parts of aplant. Exemplary types of tissue cultures are protoplasts, calli, plantclumps, and plant cells that can generate tissue culture that are intactin plants or parts of plants, such as embryos, pollen, flowers, seeds,pods, leaves, stems, roots, root tips, anthers, and the like. Means forpreparing and maintaining plant tissue culture are well known in theart. By way of example, a tissue culture comprising organs has been usedto produce regenerated plants. (See U.S. Pat. Nos. 5,959,185; 5,973,234and 5,977,445, the disclosures of which are incorporated herein byreference).

Deposit Information

A deposit of the Stine Seed Farm, Inc. proprietary soybean cultivar61646251 disclosed above and recited in the appended claims has beenmade with the American Type Culture Collection (ATCC), 10801 UniversityBoulevard, Manassas, Va. 20110. The date of deposit was Sep. 27, 2000.The deposit of 2,500 seeds were taken from the same deposit maintainedby Stine Seed Farm, Inc. since prior to the filing date of thisapplication. All restrictions upon the deposit have been removed, andthe deposit is intended to meet all of the requirements of 37 C.F.R.§1.801-1.809. The ATCC accession number is PTA-2509. The deposit will bemaintained in the depository for a period of 30 years, or 5 years afterthe last request, or for the effective life of the patent, whichever islonger, and will be replaced as necessary during that period.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity andunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the invention, as limited only bythe scope of the appended claims.

What is claimed is:
 1. A soybean seed designated 61646251, a sample ofsaid seed deposited under ATCC Accession No. PTA-2509.
 2. A plant, orparts thereof, produced by growing the seed of claim
 1. 3. Pollen of theplant of claim
 2. 4. An ovule of the plant of claim
 2. 5. A soybeanplant, or parts thereof, having all of the physiological andmorphological characteristics of the soybean plant of claim
 2. 6. Atissue culture of regenerable cells of a soybean plant of cultivar61646251, wherein the tissue regenerates plants capable of expressingall of the morphological and physiological characteristics of thecultivar
 61646251. 7. A tissue culture according to claim 6, the cellsor protoplasts being from a tissue selected from the group consisting ofleaves, pollen, embryos, meristematic cells, roots, root tips, anthers,flowers, seeds, stems and pods.
 8. A soybean plant regenerated from thetissue culture of claim 6, capable of expressing all of themorphological and physiological characteristics of soybean cultivar61646251.
 9. A method for producing a soybean seed comprising crossing afirst parent soybean plant with a second parent soybean plant andharvesting the resultant hybrid soybean seed, wherein said first orsecond parent soybean plant is the soybean plant of claim
 2. 10. Ahybrid soybean seed produced by the method of claim
 9. 11. A hybridsoybean plant, or parts thereof, produced by growing said hybrid soybeanseed of claim
 10. 12. Soybean seed produced from said hybrid soybeanplant of claim
 11. 13. A method for producing a hybrid soybean seedcomprising crossing a soybean plant according to claim 2 with a secondsoybean plant.
 14. A hybrid soybean seed produced by the method of claim13.
 15. A hybrid soybean plant, or parts thereof, produced by growingsaid hybrid soybean seed of claim
 14. 16. Soybean seed produced fromsaid hybrid soybean plant of claim
 15. 17. A method for producing a61646251-derived soybean plant, comprising: a) crossing soybean line61646251 , a sample of seed of said line having been deposited underATCC accession number PTA-2509, with a second soybean plant to yieldprogeny soybean seed; b) growing said progeny soybean seed, under plantgrowth conditions, to yield said 61646251-derived soybean plant.
 18. Themethod of claim 17, further comprising utilizing plant tissue culturemethods to derive progeny of said 61646251-derived soybean plant andwherein the regenerated plant has all of the physiological andmorphological characteristics of the plant of claim
 17. 19. A method fordeveloping a soybean plant in a soybean plant breeding program usingplant breeding techniques which include employing a soybean plant as asource of plant breeding material comprising: using the soybean plant ofclaim 2 and wherein said plant breeding techniques are selected from thegroup consisting of: recurrent selection backcrossing, pedigreebreeding, restriction fragment length polymorphism enhanced selection,genetic marker enhanced selection, and transformation.
 20. A soybeanplant, or parts thereof, produced by the method of claim
 19. 21. Thesoybean plant of claim 5, further comprising a single gene conversion.22. The single gene conversion soybean plant of claim 21, where the geneis selected from the group consisting of: a transgenic gene, a dominantallele, and a recessive allele.
 23. The single gene conversion soybeanplant of claim 21, where the gene confers a characteristic selected fromthe group consisting of: herbicide resistance, insect resistance,resistance to bacterial, fungal, or viral disease, male sterility, andimproved nutritional quality.